The present invention is directed generally to fasteners and, more particularly, to apparatus for connecting hollow tubes end-to-end with an insert.
The present invention is directed to the problem of bringing tubes together along a longitudinal or axial direction and connecting them together. In this regard, there are fastening devices which function after first moving the tubes in a transverse direction relative to one another. Many applications, however, do not allow for such movement. Even if they do, the connecting or fastening devices usually include end members having a larger transverse dimension than the transverse dimension of the tubes. Such bulky devices may not be desirable for either functional or aesthetic reasons.
Oftentimes, when tubes are moved longitudinally or axially, one is swaged to allow it to telescope into the other. Such interacting ends hold the tubes together in one axial direction, but not the other. A common positive attachment is obtained by then using a bolt and nut. Such attachment is simple, but the lines of the tubes are aesthetically broken. Further, a bolt and nut usually requires tools and are prone to complications during installation such as cross-threading.
What is needed is a fastener that disengageably engages tubes together which are longitudinally or axially moved into engagement with one another and which fastener does not extend significantly from the profile of the tubes. Further, the fastener should be easily installable and removable without tools.
In a basic form, the present invention is directed to a fastener for connecting a hollow tube and an insert member.
In one embodiment, a connecting assembly is described for connecting a hollow cylindrical tube. The tube includes a tube wall, having a pair of aligned openings. The connecting assembly includes an insert member with an outer surface formed to slide into the tube. The outer surface of the insert member has a cavity space alignable with the openings of the tube.
The connecting assembly also includes a rotating fastener with a pair of plate-like arm portions each having an end with a curved edge. Each of the arm portions is formed with a profile shaped to curve around some portion of the tube. Each of the arm portions includes a protuberance fitting into one of the openings of the tube and into the cavity space of the insert member to fasten the tube and insert member together. The rotating fastener further includes a handle member connected between the arm portions. The handle member is generally arcuate in shape and protrudes above an outer surface of the tube to form an access gap between the tube and the handle member. The handle member allows rotation of the arm portions between an engagement and a disengagement position. The engagement position is defined where the profile of the arm substantially conforms to the outer surface of the tube. The disengagement position is defined where a portion of the curved edge of the arm portions ride against the outer surface of the tube and moves the protuberances outward from the cavity space thereby substantially releasing the insert member.
The access gap may include a gap dimension defined as the radial distance between the handle member and the outer surface of the tube when the rotating fastener is in the engagement position. The gap dimension measures from 3 to 6 percent of an outer diameter of the tube, and in some cases typically about the thickness of an average human fingernail.
Each of the arm portions of the rotating fastener may further include a first and second seam located at a first and second edge of the partially circular perimeter of the arm portions. The seams are oriented generally parallel to a longitudinal axis of the tube when the rotating fastener is in the engagement position to provide an unbroken engagement surface between the tube and the arm portions.
The connecting assembly may further include a safety marking on the connector. The rotating fastener is adapted to obscure the safety marking in the engagement position. The safety marking is visible in the disengagement position. The safety marking can include a reflective element and/or a laser identifiable reflector. The safety marking can be located on the tube so that the safety marking is obscured by the handle member and/or one or more arm portions when the rotating fastener is in the engagement position.
In one configuration, the handle member of the rotating fastener further includes a leading edge generally perpendicular to a longitudinal centerline of the tube, the leading edge sloping towards the tube in the engagement position, a radial distance between the leading edge and the outer surface of the tube defining the access gap.
In another embodiment of the present invention, a connecting apparatus includes first and second longitudinally-extending, hollow tubes. The tubes have first walls and first open ends, and each of the first walls has a pair of openings. The connecting apparatus further includes a pair of fastener members. Each fastener member includes protuberances fitting in one of the pairs of openings in one of the first walls in an engagement position of the fastener members. The fastener members are rotatable about the protuberances. A pair of plate-like arm portions straddles the pair of openings and are connected to the protuberances. A lifting means is connected between the arm portions. The lifting means protrudes above an outer surface of the tubes to form an access gap. A disengagement means moves the protuberances outward from the openings when the fastener members are rotated about the protuberances to a disengagement position of the fastener members.
The connecting apparatus further includes an insert member having a second wall formed to slide longitudinally into the first open ends of the tubes. The insert member includes means for moving the pair of connected protuberances of each of the fastener members and means for receiving the protuberances so that the protuberances can engage the tubes and the insert member.
The moving means of the insert member may include a tapered end on the insert member. The insert member may also include first and second parts, and holding means for holding the first and second parts together. The holding means includes means for supporting an accessory extending transversely from the insert member. In one configuration, the holding means includes threaded openings in facing ends of the first and second parts and a threaded rod received in each of the openings. In another configuration, the accessory is a plate having openings for receiving the threaded rods in regions between the first and second parts.
The connecting apparatus may further include a safety marking, the safety marking obscured by the fastener members in the engagement position. The safety markings may include a reflective element and/or a laser identifiable reflector. The safety marking can be located on at least one of the tubes so that the safety marking is obscured by one or more arm portions and/or the lifting means of the fastener members in the engagement position.
The lifting means of the fastener members may include a leading edge generally perpendicular to a longitudinal centerline of the tube, the leading edge sloping towards the tube when the protuberances engage the tubes and the insert member, a radial distance between the leading edge and the outer surface of the tube defining the access gap.